Gelatin and gelatin derivatives are used to encapsulate the products of several industries. Examples are described in U.S. Pat. No. 5,074,102 of Simpson et al. issued Dec. 24, 1991, and include the encapsulation of medicinal compounds such as drugs or vitamins; employment of gelatin encapsulation in food packaging, such as for powdered instant coffee or spices; in candy manufacturing; in fertilization of ornamental plants and/or indoor plants; in packing of sensitive seeds in combination with protective agents and/or fertilizers; and in the packing of single dyestuffs or mixtures of various drugs.
In each of the above-recited manufacturing and production processes, a certain amount of the encapsulating material is lost as waste. Frequently, this amount approaches 50% or more, depending on the method and arrangement of production employed. When considering that the cost of the encapsulating material in the United States averages approximately $1.80 per pound ($3.40 per kilo), it is clear that the economic consequences of such waste can be significant. As a result, manufacturers have attempted to off-set poor production efficiency by recycling the waste material for reuse. Such attempts, however, have not been met with a great deal of success.
Prior art methods of gelatin recovery and purification suffer from a variety of shortcomings to be discussed in further detail below. Before these shortcomings can be fully appreciated, however, the composition of the encapsulation waste material itself should be further understood. In general, waste material of encapsulation processes are comprised of a variable number of components added to a gelatin base. Among them are solvents (usually water); softening agents and oil coatings (when desired) and contaminants in the form of residual active ingredients (the substance to be encapsulated). In addition, colorings and preservatives may also be added. Thus, it can be observed that successful recycling involves not only the recovery of gelatin from surrounding oils, but also the removal of the remaining components of the waste, to achieve a pure, reusable product.
Extraction has been the principle method for accomplishing removal of oils, actives and the like in the pharmaceutical industry. While several solvents have been used in the prior art in an effort to accomplish separation, each suffer from a variety of shortcomings not the least of which is the necessity of ultimately removing yet another component, the solvent itself, from the recycled materials. To date, the most popular and widely used solvents used to separate gelatin from oils and actives are chlorinated solvents such as 1,1,1-trichloroethane with naptha, for example. The use of chlorinated solvents, however, is accompanied by high costs, disposal problems and most importantly, environmental concerns. Other solvents have also been attempted, including: isopropyl alcohol, methyl isobutyl ketone, toluene, hexane, acetone and acetone:water mixtures, but with insufficient yields and/or poor separation results. Some of these chemicals are relatively expensive and present similar environmental, disposal and safety concerns. None of them have been found to separate out oils and actives with a high degree of efficiency.
It is clear that a significant need exists for a solution that addresses not only qualitative and quantitative concerns with the recycled end-product, but also the practical considerations of cost and environmental safety. Little progress had been achieved in developing a comprehensive solution that completely obviates all of the shortcomings of prior art until the advent of the subject invention described below.